Cyclone separator

ABSTRACT

A cyclone separator has with a separation chamber in a spiral housing fitted with an inlet for the material to be separated in parallel to a tangent to the separator housing, a separate tangential inlet for a separator gas, and a longitudinal outlet arranged concentrically about the separator axis to allow the gas and fine particulate matter to pass out of the separation chamber. The separator further has a ring of vanes located in the spiral housing between the separation chamber, which is arranged coaxially to the outlet, and an outer annular space, the material inlet feeding into the separation chamber and the gas inlet feeding into the outer annular space.

BACKGROUND OF THE INVENTION

The present invention pertains to a cyclone separator, which has as theprincipal components a spiral housing with inlets for raw material andseparator gas, a separator wheel, a ring of vanes, and outlets forcoarse and fine particulate matter as well as the separator air. Thepresent invention is a novel design of such a cyclone separator, inwhich it is possible to carry out an operating method whichfundamentally differs from the prior art operating methods and providesparticularly good separation results without extra expense foradditional structures.

However, it seems best for the understanding of the present invention touse German Offenlegungsschrift No. DE-OS 24,26,295 as the startingpoint, because the design of a cyclone separator according to thepresent invention seems to differ only slightly from a cyclone separatoraccording to this prior-art reference, but the completely different modeof operation of a cyclone separator according to the present inventioncan be explained particularly well in comparison with this prior art.

DE 24,26,295, which is the closest prior art, is based on a cycloneseparator, in which the material to be separated is introducedtangentially to the inner circle of a stationary vane ring withadjustable vanes, to the outer circle of which the separator air istangentially introduced. The front walls of the separation spacesurrounded and delimited by the vane ring are rotatable just as thematerial to be separated in order to reduce frictional losses. The vanesof the vane ring are dimensioned and adjustable such that the materialto be separated is separated into coarse matter and fine particulatematter in the separation space. The coarse matter is fed, near the innercircle of the vane ring, to a strip-off edge and is separated from thearea of the fine particulate matter by means of the strip-off edge, tobe fed to the coarse matter outlet. The remaining mixture of separatorair and fine particulate matter is fed to the fine particulate matteroutlet in a flow forming a sink. The present invention is based on theconsideration that there is a risk in such cyclone separators thatso-called spray particles will enter the fine particulate matter,already separated from the coarse matter, from the coarse matter locatedin front of the strip-off edge, so that the fine particulate matter willstill contain a possibly small, but unintended percentage of coarsematter in the form of the above-mentioned spray particles. To eliminatethis disadvantage, a coarsely separating separator wheel, which againseparates the coarse matter component from the fine particulate matterby applying the centrifugal action, is arranged in the fine particulatematter outlet. Consequently, a high design expense is required in theform of the separator wheel merely to separate the small percentage ofspray particles from the fine particulate matter. In addition, it isdifficult to adjust the vanes of the stationary vane ring such that boththe crude gas flow interspersed with the material to be separated in awell-dispersed form is introduced and good separation of the coarsematter from the fine particulate matter takes place. Only a compromisebetween these two requirements is possible, as a rule.

SUMMARY OF THE INVENTION

The present invention takes a different approach insofar as theseparation of the fine particulate matter from the coarse matter doesnot take place in a separation space, in the outlet of which a separatorwheel is arranged specifically for final purification of the fineparticulate matter already separated from the coarse matter. Instead, aseparator wheel is provided for the actual separation of the coarsematter component from the fine particulate matter component. Thestationary vane ring in a separator used for the present invention iscorrespondingly designed such that the separator air, which is dispersedwith the fine particulate matter and the coarse matter in a welldispersed form, is introduced in the most uniform distribution possibleto the circumference of and into the separator wheel. The separationinto coarse matter and fine particulate matter takes place in theseparator wheel, which is directly preceded by the vane ring. The vanering has the exclusive task of optimally dispersing the raw material inthe separator air and of feeding the flow of raw material thus processedto the separator wheel in a uniformly dispersed form, rather than in avane-surrounded, stationary separation space, as in the above-describedprior art, which is followed by a final-purification separator wheel(removal of spray particles, whose mass is several times the mass of theparticles of the fine particulate matter, from the flow of fineparticulate matter).

Separator wheels designed for this task have been known per se (e.g., EP89121065.0). However, arranging a vane ring upstream of such separatorwheels in the above-described manner has been unknown.

There is an essential difference between the closest prior art and thepresent invention with respect to the "strip-off edge" as well, becausethe coarse matter is stripped off with the strip-off edge in the priorart, whereas a guide edge according to the present invention deflectsonly coarse particles, which do not enter, as intended, the separatorwheel, despite the vane ring of corresponding design, and consequentlymay possibly correspond, in terms of their amount, to the spray particlecomponent according to the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained with reference to the drawings,

FIG. 1 shows a vertical central longitudinal section through a cycloneseparator designed and operating according to the present invention,

FIG. 2 shows a horizontal central longitudinal section through thecyclone separator according to FIG. 1, corresponding to line A--A inFIG. 1, and

FIG. 3 shows a section corresponding to FIG. 2, in which the separatorwheel has, however, been omitted to show the guide edge, which islocated behind the separator wheel in the sectional view in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A separation chamber 9 is surrounded by a stationary vane ring 11. Vanes12 of the vane ring 11 are individually adjustable around theirrespective longitudinal axes 13. The vane ring 11 forms part of a circlelocated concentrically to the separator axis 6.

A prior-art, rotating separator wheel 14, which has vanes 15, isarranged in the separation chamber 9 surrounded by the vane ring 11,likewise concentrically to the separator axis 6. The annular spacebetween the outer circle of the separator wheel 14 and the inner circleof the vane ring 11 is substantially narrower than in the prior art,because no actual separation is to take place in it, contrary to theprior the art. The width of the annular space between the separatorwheel and the vane ring is selected only to be such as is necessary forthe ordered passage of the raw material from the vane ring into theseparator wheel.

The inlet 3 for the material to be separated opens tangentially into theseparation chamber 9 in the area of the annular space between the vanering 11 and the separator wheel 14. The separator air inlet 5 openstangentially into the annular space 17 between the vane ring 11 and thesaid spiral housing 1. The inlet 3 for the material to be separated andthe said separator air inlet 5 are pipes arranged in parallel to oneanother. A spray particle outlet 8 having a guide plate 18, which ispositioned obliquely by at least 45°, is attached to a wall section 19of the separator housing, and separates the inner separation chamber 9from the outer annular space 17 together with a wall section 20 attachedto the pipe 2 of the inlet 3 for the material to be separated. The guideplate 18 is located, with one of its edges, at the circumference of thevane ring 11 toward the end of the flow path in the separator housing,i.e., toward the inlet 3 for the material to be separated, and with itsother end close to the separator wheel 14 to the extent permissible forunhindered rotary movement of the separator wheel 14.

The separator air flows through the flow channels between the vanes 12of the said vane ring 11 from the outside to the inside. The vanes 12are mounted rotatably in the housing 1 such that both the angle at whichthe separator gas flows in and the gap width of the flow between thevanes 12 can be varied. The material to be separated is charged in onthe inside of the said vanes 12 of the vane ring 11, and the separatorgas flows intensely through it at the gaps between the vanes 12. Vortexformation, which prevents material to be separated from settling on thevanes, becomes established in the flow channels between the vanes of thevane ring 11 because of the prevailing flow conditions brought about bythe setting and the shape of the vanes. A spiral flow becomesestablished in the separation chamber 9, and some separation, althoughslight and undesired, takes place in the spiral flow. Particles thatrotate in the separation chamber 9 at the velocity v_(u),G are forced tothe outside by a centrifugal force F_(T). At the same time, the sweepingforce F_(W), which is caused by the radial velocity of the gas, V_(r),G,mainly causes particles to be swept toward the inside of the separationchamber 9.

The same physical relationships prevail in the separator wheel 14 withthe vanes 15, which is arranged concentrically in the separation space9; however, the radial and circumferential velocities are influencedhere by the gas mass flow and the speed of the separator wheel 14,rather than by the gas mass flow and the vane setting. In order for theseparator wheel 14 to determine the fineness, the separation limit,i.e., the gaps between the vanes 12, leading to the annular space 9 isset to be coarser in the annular space than on the separator wheel 14.

Thus, the outer vane ring 11 is used for a relatively slightpreseparation and, especially, for the intense dispersion anddisintegration of the material to be separated, which can be consideredto be an essential advantage, and which can be achieved with the presentinvention. The actual separation takes place at high efficiency in theseparator wheel, and the particles deflected by the deflecting device 8represent, in a manner of speaking, a spray material consisting ofparticles of extremely high mass and particles which are subject tospecial influences; in fact, the overwhelming majority of the particlesare caused to enter the separator wheel, which is used for the actualseparation.

The fine particulate matter finally leaves the separator via the productor fine particulate matter outlet 7 of the separator wheel 14; spraymaterial, which circulates close to the vane ring 11, is preferablystripped off via the guide plate 18 of the spray particle outlet 8,which is set obliquely by at least 45°, and can thus be removed from theseparation space.

The vanes 12 of the said outer, static vane ring 11 are set such thatthe flow angle of the vanes 12 and the cross sections of the vanechannels between the vanes lead, according to the present invention, toa spiral cyclone separation, which yields a coarser separation size thanwould correspond to the conditions prevailing at the outer edge of thevane-type separator wheel in the annular separation space 9 between thevane ring 11 and the vane-type separator wheel 14.

The sectional view according to FIG. 2 shows parts of the separatoraccording to FIG. 1 with the reference numerals used in FIG. 1, withoutthe spray particle edge 18 and the spray particle outlet 8.

The section according to FIG. 3 correspondingly shows the parts of FIG.1 with the reference numerals of FIG. 1, without showing the separatorwheel 14, but the setting angle α of the spray particle edge 18, whichshall be at least 45° according to the present invention, isrecognizable.

To meet the criterion of small width of the annular space between thevane ring 11 and the separator wheel 14, the ratio of the diameter ofthe vane ring 11 to the diameter of the separator wheel (ratio of thecentral circle of the vane ring to the central circle of the separatorwheel) shall be preferably 1:0.8 and, at most, 1:0.65. The setting angleof the vanes 12 of the vane ring to a tangent to the circumference ofthe vane ring shall be preferably 25°.

The separator is arranged vertically according to FIG. 1 (withhorizontal separator axis 6), but a horizontal arrangement with verticalseparator axis 6 is possible.

The spray particle outlet 18 has the guide plate 8 and an opening in thewall (which is the rear wall relative to the representation in FIG. 1)of the separator housing, to which the guide plate 8 leads.

Since no separation is to take place in the annular space 17, thisannular space may have constant width, even though it may also becomenarrower in the direction of flow.

I claim:
 1. Cyclone separator with a stationary spiral housing, a vanering stationarily arranged in the spiral housing, said vane ring havingadjustable vanes, a separator wheel arranged coaxially within the vanering, means for tangentially introducing crude gas and separator gasinto said housing, and guide edge means for deflecting coarse particlesin an end zone of a spiral flow in an annular space between the vanering and the separator wheel, comprising(a) a first tangential inletpipe for the introduction of material to be separated into the annularspace between the vane ring and the separator wheel; (b) a secondtangential inlet pipe for the introduction of separator gas, arranged inparallel to the first inlet pipe for the introduction of the material tobe separated; (c) means for mixing the separator gas introduced throughthe second inlet pipe with the material to be separated, introducedthrough the first inlet pipe; (d) outlet means in the form of a guideplate at an end of a flow path for the material to be separated, saidguide plate being placed obliquely to the flow in the annular spacebetween the vane ring and the separator wheel, inclined in relation toan axis of the separator and having one of its edges on thecircumference of the vane ring, being attached to a wall section of theseparator housing, and having another edge proximate to the separatorwheel, and (e) an outlet means for fine particulate matter, arrangedconcentrically in said annular space.
 2. Cyclone separator in accordancewith claim 1, wherein the angle of the guide plate to the separator axisis at least 45°.
 3. Cyclone separator in accordance with one of theclaims 1 and 2, wherein the ratio of the diameter of the vane ring tothat of the separator wheel is at most 1:0.65.
 4. Cyclone separator inaccordance with one of the claims 1 and 2, wherein the ratio of thediameter of the vane ring to that of the separator wheel is 1:08. 5.Cyclone separator in accordance with claim 1 wherein the angle of thevanes of the vane ring to a tangent to the circumference of the vanering is 25°.
 6. Process for separating course material and fine materialin a gas comprisinginjecting said gas with said material into a cycloneseparator having a stationary spiral housing, a vane ring stationarilyarranged in the spiral housing, said vane ring having adjustable vanes,a separator wheel arranged coaxially within the vane ring, means fortangentially introducing said gas with said material and a separator gasinto said housing, and guide edge means for deflecting coarse particlesin an end zone of a spiral flow in an annular space between the vanering and the separator wheel, said separator comprising (a) a firsttangential inlet pipe for the introduction of material to be separatedinto the annular space between the vane ring and the separator wheel;(b) a second tangential inlet pipe for the introduction of separatorgas, arranged in parallel to the first inlet pipe for the introductionof the material to be separated; (c) means for mixing the separator gasintroduced through the second inlet pipe With the material to beseparated, introduced through the first inlet pipe; (d) material outletmeans in the form of a guide plate at the end of a flow path for thematerial to be separated, said guide plate being placed obliquely to theflow in the annular space between the vane ring and the separator wheel,inclined in relation to an axis of the separator and having one of itsedges on the circumference of the vane ring, being attached to a wallsection of the separator housing, and having another edge proximate tothe separator wheel, and (e) outlet means for fine particulate matter,arranged concentrically in said annular space.